1. Field of the Invention
The present invention relates to a flat panel display device, and more particularly to a flat panel display device that is adaptive for optimizing data, which are to be displayed in a panel defect area, in used of a compensation value of a compensation circuit as well as compensating defect pixels by a repair process, and a method of controlling a picture quality thereof.
2. Description of the Related Art
Recently, there has been paid attention to various flat panel display devices which can reduce their weight and size that are a disadvantage of a cathode ray tube. The flat panel display devices include a liquid crystal display device, a field emission display device, a plasma display panel, an organic light emitting diode and the like.
The flat panel display device includes a display panel for displaying a picture, and there might be a case that a picture quality defect is found in a test process of the display panel.
The cause of the picture quality defect occurring in the test process of the display panel results from a defect in a process, and the picture quality defect is generated because there is a defect in the display panel. The panel defect can be, for example, an exposure deviation in an overlapping exposure process, a lens aberration of an exposure device and the like. The panel defect caused by the process deviation might be generated in a fixed form such as dot, line, belt, circle, polygon and the like or in an indeterminate form, as in FIGS. 1 to 5.
In order to recover the panel defect, a repair process inclusive of a thin film forming process, a patterning process and the like is carried out, but it is limited to the recover of the panel defect even though the repair process is carried out. And, the panel is disposed as a waste in case that the panel defect is heavy. Further, in most cases, the brightness or chromaticity of an area where there was the panel defect is shown differently from that of a non-defect area even though the repair process was carried out.
The repair process for a pixel defect shown in a dot shape among the panel defects includes a method of turning the defect pixel into a dark point. But, in the method of making the dark point, the dark point is almost not perceived in a black gray level, as shown in FIG. 6A, but the dark point is clearly perceived in the display screen of an intermediate gray level and a white gray level, as shown in FIGS. 6B and 6C.
As a result, there is a limit in improving the picture quality deterioration, which is caused by the panel defect, only by the repair process for recovering the panel defect.